Field of Science

Wigs and Wings and Other Things

Congratulations go to Adam Yates for successfully identifying this animal:

Arixenia esau, photographed in Deer Cave in Sarawak by Alan Cressler.

This "very interesting, though repulsive, insect" (to use the words of Hebard in 1927) is a member of today's Taxon of the Week, the Neodermaptera. Neodermaptera is the clade containing all living members of the Dermaptera, the earwigs, distinguished from various stem groups of the Dermaptera by features such as three-segmented tarsi and the lack of veins in the forewings (Engel 2003). Earwigs are one of the few groups of insects other than beetles to have the forewings hardened into elytriform cases, which in earwigs have also been greatly reduced in size (in earwigs, the hardened forewings are referred to as 'tegmina' rather than 'elytra', but these seem to be just different words for much the same sort of thing). The rarely-seen hindwings remain folded under the tegmina unless the earwig is flying (which they do not often do) and are simply bizarre. One of the characteristics of polyneopterans, the group of insects including crickets, cockroaches, earwigs and various others, is a tendency towards enlargement of the anal fan, the posterior part of the wing; in earwigs, the anal fan of the hindwing has become enlarged to the point that the wing is almost entirely anal fan with the anterior parts of the wing greatly reduced and crammed into a small toughened section towards the base. One of the stories floating about to supposedly explain the origin of the name 'earwig' claims that it is a corruption of 'ear-wing'. While the wings are indeed ear-shaped, the story rather loses credibility in face of the detail that the average person would probably never see them.

Earwig (probably a female Doru using the key in Engel 2003) with its wings spread, showing the semicircular shape and radiate anal veins. Photo by Sean McCann.

The other distinctive feature of most living earwigs is the development of the cerci at the end of the abdomen into a pair of large, hard forceps. The forceps are used for defense as well as capturing prey in those species that eat animal matter (most earwigs are omnivorous); they may also be used to help fold the wings under the tegmina. In most species, the males have heavier forceps than the females. The only earwigs to have filamentous cerci rather than forceps are the Arixeniidae and Hemimeridae, two families that live in association with mammalian hosts. Arixeniids (such as Arixenia in the top picture) are about 2 cm long and live on bats in south-east Asia; hemimerids are about half that size and live on African giant rats. Not are they distinctive among earwigs, they are the only known quasi-parasitic polyneopterans—I say 'quasi'-parasitic because they probably feed more on dead skin and host secretions than the actual living host itself. The arixeniids probably feed mostly on the rich deposits of bat poo in host roosting sites. Because of the lack of forceps and other features, these two families have often been placed in separate suborders from the remaining earwigs; at least one author argued that hemimerids should be removed from Dermaptera entirely and treated as a separate order. However, the current consensus is that the two families are probably derived from more normal earwigs, with their distinctive features being adaptations to their symbiotic lifestyles.

Forceps of the recently extinct Labidura herculeana of St Helena, the largest known earwig, alongside a 22 mm specimen of its more average close relative L. riparia. Photo by Philip Ashmole.

Another distinctive feature of the two mammal-associated families is that they are live-bearers. In all other families, the female lays a batch of eggs, usually in a burrow, that she watches over until the young hatch out. She continues to protect her young for their first one or two instars; after that they must fend for themselves. In fact, if the young do not move out quickly enough, their mother will eat them (Rentz & Kevan, 1991). Something, perhaps, to be kept in mind by all those parents who feel their adult offspring are taking too long to get their own place.


Engel, M. S. 2003. The earwigs of Kansas, with a key to genera north of Mexico (Insecta: Dermaptera). Transactions of the Kansas Academy of Science 106 (3-4): 115-123.

Hebard, M. 1927. Studies in Sumatran Dermaptera. Proceedings of the Academy of Natural Sciences of Philadelphia 79: 23-48.

Rentz, D. C. F., & D. K. McE. Kevan. 1991. Dermaptera (earwigs). In: CSIRO. The Insects of Australia, 2nd ed., vol. 1, pp. 360-368. Melbourne University Press.

Name the Bug # 30

If I'm continuing with the supposed pattern of these challenges, it's time for an easy one:

But because it is relatively simple, I'm going to want at least a genus ID (and preferably some supporting info).

Attribution to follow.

Update: Identity available here. Photo from here.

Archechiniscus: Distinctively Indifferent

Archechiniscus marci. Figure from Pollock (1976).

Archechiniscus is a genus of three species of marine tardigrade found in littoral habitats. They can be readily distinguished from other marine tardigrades by their unique arrangement of claws: two pairs, with the internal pair on the end of a long pair of toes but the external pair set directly onto the foot. Most of the other distinguishing features of Archechiniscus are more negative: they lack conspicuous segmentation or ornamentation. The presence of cephalic appendages marks Archechiniscus as belonging to the heterotardigrades rather than the eutardigrades; within the Heterotardigrada, it belongs to the paraphyletic 'arthrotardigrade' group. Opinions have differed as to whether it should be placed in the family Halechiniscidae or in its own separate family; Jørgensen et al. (2010) identified the broad Halechiniscidae as polyphyletic and plumped for placing Archechiniscus in its own family (though potentially as the sister group of their more restricted Halechiniscidae).

As for most marine tardigrades, there doesn't appear to be a great deal of info about the lifestyle of Archechiniscus. Archechiniscus symbalanus got its name due to being collected in association with barnacles (Chang & Rho, 1998) but I don't know what it was doing there. As littoral inhabitants, Archechiniscus are resistant to a higher degree of desiccation than other marine tardigrades (Jönsson & Järemo, 2003) but do not show the extremes of resistance found in some other tardigrades (remember, not all tardigrades are resistant to adverse conditions, and not all tardigrades are resistant to the same adverse conditions).


Chang, C.-Y., & H.-S. Rho. 1998. Three new tardigrade species associated with barnacles from the Thai coast of Andaman Sea. Korean Journal of Biological Sciences 2: 323-331.

Jönsson, K. I., & J. Järemo. 2003. A model on the evolution of cryptobiosis. Annales Zoologici Fennici 40: 331-340.

Jørgensen, A., S. Faurby, J. G. Hansen, N. Møbjerg & R. M. Kristensen. 2010. Molecular phylogeny of Arthrotardigrada (Tardigrada). Molecular Phylogenetics and Evolution 54 (3): 1006-1015.

Pollock, L. W. 1976. Marine Flora and Fauna of the Northeastern United States. Tardigrada. NOAA: Seattle.

Name the Bug #29

I've been accused of swinging wildly between the easy and the impossible for these ID challenges. The last one was fairly easy, so I suppose it's time for the impossible:

To give a bit of a hand, the animal shown is a marine species of its phylum.

Attribution to follow.

Update: Identity available here. Figure from Pollock (1976).

Borage and Comfrey and Bugloss

Anchusa undulata ssp. granatensis. Photo by James Gaither.

The tribe Boragineae includes about 170 species of herbaceous flowering plants, mostly found in the Palaearctic region with only a couple of species extending into southern Africa. The group is well-distinguished by the presence of what are called fornices, the whitish lobes at the base of each petal that you can see in the photo above, as well as features of their seeds. Many Boragineae seeds have an elaiosome, a fatty plug at one end that attracts foraging ants (Hilger et al., 2004). The ants carry the seed back to their nest as food, but the plant produces enough seeds that at least some will not be eaten but will be able to germinate after being carried under the ground and away from anything else that might eat them.

Abraham-Isaac-Jacob, Trachystemon orientalis, a native of forests around the Black Sea and one of the more unusual species of Boragineae. Apparently the unusual name refers to the flowers changing colour as they age. Photo by Daniel Mosquin.

The species are divided between about fifteen genera (the exact number varies depending on whom you ask). The largest generally-recognised genus, Anchusa (the buglosses), was identified by Hilger et al. (2004) as para-/polyphyletic with a number of smaller genera also nested within the Anchusa clade, suggesting that the currently recognised constituent subgenera may need to be recognised as separate subgenera (or else the genera Lycopsis and Cynoglottis submerged into Anchusa). Other relationships within the tribe recognised by this and other studies include a close relationship between the genera Borago (borage) and Symphytum (comfrey), and between Nonea and Pulmonaria (lungwort). The basalmost member of the tribe is Pentaglottis sempervirens, which is also the only member of the tribe found in the Atlantic region of southwest Europe. The relict distribution of this species, as well as the concentration of diversity for the tribe overall, have been cited as supporting a Mediterranean origin for the Boragineae.

Green alkanet, Pentaglottis sempervirens, the sister species to all other Boragineae. Photo by Carl Farmer.

A number of members of the tribe have long been cultivated and many are even labelled by their botanical names as officinal (the Medieval Latin term 'officinalis' refers to a plant or substance that is kept in an apothecary; not surprisingly, many plants with supposed medicinal values are also eaten for their nutritional values). Borago officinalis, borage, is used as a salad or pot herb in Europe. Symphytum officinale, comfrey, has also been widely used medicinally, mainly for external uses such as soothing bruises (some of the properties attributed to comfrey verge on the ridiculous: a bath steeped in comfrey was supposedly able to restore a woman's virginity). Pulmonaria officinalis, lungwort, received its name because of the supposed resemblance of its blotchy leaves to lung tissue. Under the unabashedly loopy herbalist principle known as the Doctrine of Signatures, this outward resemblance indicated its suitability in treating lung diseases such as tuberculosis (in fact, lungwort contains toxic alkaloids that make it dangerous to take internally).


Hilger, H. H., F. Selvi, A. Papini & M. Bigazzi. 2004. Molecular systematics of Boraginaceae tribe Boragineae based on ITS1 and trnL sequences, with special reference to Anchusa s.l. Annals of Botany 94 (2): 201-212.

Name the Bug # 28

Tomorrow's Taxon of the Week will certainly be bringing the pretty:

Anyone recognise it?

Attribution to follow.

Update: Identity now available here. Photo from here.

Thoughts Inspired by a Private Publication

A number of sources, including this message on the DML archive, drew my attention yesterday to the existence of a recent online publication proposing a new North American sauropod species 'Amphicoelias brontodiplodocus', as well as synonymising a whole slew of other familiar dinosaur taxa (such as Apatosaurus and Diplodocus) under the relatively unfamiliar name Amphicoelias. Quite apart from 'Amphicoelias brontodiplodocus' perhaps being the most intensely unaesthetic name ever proposed for a dinosaur (and this in a field including such wince-inducing monikers as Raptorex and Tyrannotitan!), the pdf has once again lifted the lid on a number of arguments that have been simmering away for some time now. I recommend reading the responses to the DML message linked to above, as well as Mike Taylor's discussion at SV-POW. I'm not in a position to discuss the technical details of the 'brontodiplodocus' pdf itself but I would like to discuss some of the broader issues raised by it, the questions of regulating publication and of publications based on privately owned specimens.

It should be noted that the 'brontodiplodocus' pdf currently appears to be an online document only and hence not validly published in the view of the ICZN (and whatever its publication status, there is no obligation on anyone else to accept the proposed synonymies). However, Mike Taylor has pointed out that it would be a simple matter for the publishers of the document to produce it in printed form and thereby validate it. Also, it would be easy for a non-expert in taxonomic procedure (and even a few supposed experts in taxonomic procedure) to mistake the current pdf for a valid publication as it is. As I've noted before, end-users of taxonomy should not be required to consider ICZN esoterica every time they are presented with a new name, just as non-specialist computer users should not always have to familiarise themselves with thousands of lines of computer code before using a new word-processing programme.

While self-publication of poor-quality works has always been a potential issue for taxonomy and the ICZN, modern technology has made self-publication much easier than before. It can now pontentially be done by anyone with access to a word processor of some form: i.e. pretty much everyone in the developed world and a large number of people in the developing world. Some have suggested that, to counteract this issue, only names published in peer-reviewed journals should be accepted as valid (I've pointed out why I disagree with this proposal in an earlier post). Others have suggested taking this even further and establishing a single journal for the publication of all zoological taxonomy. This is already the method used by the Prokaryote Code of Nomenclature, which requires that all new bacterial taxa be published or validated in the International Journal of Systematic and Evolutionary Microbiology. However, it is debatable whether such a model could be applied to the ICZN. Firstly, the sheer number of new zoological names published each year is much higher than the number of bacterial names, perhaps by a few orders of magnitude. A single zoological taxonomic journal would be a major undertaking, especially for an organisation such as the ICZN which lacks any major sources of funding on which to draw. Secondly, the Prokaryote Code of Nomenclature has very high basic requirements for a taxon to be considered published (such as deposition of cultures of the type strain in two separate collections in separate countries). It is unlikely that the ICZN would be able to implement such across-the-board requirements because it deals with a much broader range of organism types (such as fossils and protozoans) than the bacterial code, each of which may have their own specialised requirements for appropriate typification.

In addition, one of the reasons that prokaryote nomenclature functions so well under these restrictions is the usage of a wide range of what might be called 'grey taxa', taxa widely regarded as recognisable but which, for various reasons (most commonly their inability to date to be cultured in the laboratory), cannot be 'validly' published (one such taxon that I've previously discussed is the minute 'Nanoarchaeum equitans'). Bacterial nomenclature therefore has two distinct nomenclatural classes of taxa. This is not necessarily a problem: 'grey taxa' cannot compete for priority with 'valid taxa', for instance, which reduces the chance of an old poorly-characterised name supplanting a newer familiar one.

The current version of the ICZN does allow in Article 79 for the potential publication of Lists of Available Names for selected taxa. Under this article, a list could be published of (for instance) all published bird names that would become the definitive listing for that group. Any names published prior to the list's end-date that were not included are regarded as unavailable (and hence not competing for priority with names included in the list), even if they normally would be under the general rules of the code (the Prokaryote Code followed this path with the publication of the Approved Lists that were the foundation of current bacterial nomenclature). To date, I am not aware of any such list being successfully ratified by the ICZN (it would not be a simple process), but the facility is potentially there. At present, the Lists of Available Names are only intended to clarify the status of previously published names rather than regulate any published subsequent to the relevant list. However, even if it is not currently feasible to introduce a single journal model for all zoological nomenclature, perhaps it could be done for specific groups? Imagine if a List of Available Names could be published for (say) dinosaurs, with a requirement that all subsequent names be validated by a prominent journal such as the Journal of Vertebrate Paleontology? (On the flipside, there would have to be a requirement that the journal must validate all names that meet certain pre-existing requirements [as currently exists for the IJSEM] in order to prevent names being refused for reasons unrelated to the diagnosability of the taxa concerned, such as personal disputes between taxonomists.) If done on a group-by-group basis, such a process might also allow for workers in each group to determine the appropriate requirements for that group.

The second major issue raised by the 'Amphicoelias brontodiplodocus' pdf is that its publishers are commercial fossil dealers and at some point the brontodiplocus 'holotype' may (probably will) be privately sold. The ICZN currently recommends, but does not require, that the type material for new taxa be deposited in publicly accessible collections. If a specimen is privately held, it is less likely to be available for study by future researchers (however, it is worth noting that a privately held specimen is not always unavailable, nor is a specimen in a public collection necessarily available). In the case of fossils, some people are of the opinion that their commercial sale should be banned completely in order to prevent scientifically significant material from entering private hands. However, not all fossil material is scientifically significant—some fossils are extremely abundant (to the extent that some localities have profitable fossil mines) and there would seem to be little sense in banning the sale of a fossil species for which thousands are already held in public collections. If the possibility is floated of only banning the sale of 'scientifically significant' specimens, we run afoul of the problem of specifying how to determine which specimens are scientifically significant. For instance, articulated Tyrannosaurus skeletons are very rare and of great scientific interest, but isolated Tyrannosaurus teeth are very common (or so I've heard) and of little scientific interest. Where exactly does one draw the line?

Type specimens, however, are by definition of scientific interest, and it is usually clear whether a specimen is a type. So while it would be somewhat ridiculous to ban the commercial sale of all fossils, perhaps it would be reasonable to preclude the commercial sale of type material? Note that I am not suggesting banning the use of privately held material in describing taxa, only that such material could not be subsequently traded*. I can think of two potential issues that might have to be considered in such a scenario. One is that commercial collectors may refuse to allow any examination of material that they hold by researchers to prevent its effective devaluation (of course, some may not see this as a problem). Another potential problem would be if a privately owned specimen is made part of the type material of a new species without the informed consent and/or involvement of the specimen's owner.

*The distinction between privately and publicly owned specimens is a lot fuzzier than those working outside the taxonomic field might expect. Many new species are described by authors on the basis of specimens they have themselves collected; while the authors may intend on eventually depositing the specimens in a public collection, this may not have yet happened at the time of publication. Depending on circumstances, it may be some time before the specimen(s) are finally passed on to the collection**.

**To give an example from my own experience, two years ago I published the new harvestman species Templar incongruens based on two specimens previously held at the Western Australian Museum that had been collected in Canterbury, New Zealand. It was decided that the new types should be transferred to the Canterbury Museum as it seemed more appropriate for them to be held in a collection in their home country, and this was the depository recorded in the publication. However, because T. incongruens has also formed part of my phylogenetic analysis of Monoscutidae currently in preparation, the specimens have not yet actually made it to Canterbury: they're still sitting in my lab here in Perth.

Small lizards of South America

Three readers made comments about the apparent identity of yesterday's ID challenge; none of them, I'm afraid, even came close.

The gymnophthalmid lizard Leposoma hexalepis, photographed in Venezuela by Carl Franklin.

Gymnophthalmids are a family of nearly 200 species (new ones continue to be described at a steady rate) of small (4-15 cm excluding the tail) insectivorous lizards from South America. So little regarded is this family that no really good vernacular name exists for it and its members are generally referred to by what they are not: they are referred to as 'microteiids' in contrast to the related but physically larger family Teiidae. Today's Taxon of the Week is a clade within the Gymnophthalmidae known as the Ecpleopini or Ecpleopinae*, depending on whom you ask.

*Technically, that should be 'Ecpleopodini', but all recent publications have used the 'incorrect' spelling (so far I've only seen one publication from 1887 use the correct spelling). The online page for one recent article includes a footnote mentioning the correct spelling but the note does not appear to be present in the printed article.

The Ecpleopini include (at present) about thirty species, about half of which are placed in the genus Leposoma. The clade is currently supported by molecular analyses without any identified morphological synapomorphies (Pellegrino et al., 2001; Rodrigues et al., 2005). Different analyses recover different relationships between the constituent genera except for a small clade of the genera Colobosauroides, Dryadosaura and Anotosaura (Rodrigues et al., 2005). This clade represents one of a number of lineages within Gymnophthalmidae to develop an elongate body form and reduced limbs together with a fossorial lifestyle. Anotosaura has also lost its external ear openings.

Another ecpleopin, Arthrosaura reticulata, photographed in Peru by Thomas Stromberg.

The species of the genus Leposoma are more generalised in their overall appearance but still not without their intrigues. Leposoma species can be divided between two groups distinguished by their chromosome number and arrangement. The L. scincoides group possess 52 chromosomes of a range of sizes while species of the L. parietale group ancestrally possess 44 chromosomes with a clear size distinction between 20 major and 24 minor chromosomes. The only exception to this pattern is L. percarinatum, a parthenogenetic species* from Mato Grosso in Brazil with 66 chromosomes: one of the few known examples of a triploid genome in vertebrates. When the triploid nature of L. percarinatum was identified, it was suggested that it might be derived from a hybridisation event between two diploid parents. Since then, a diploid form of L. percarinatum has also been identified that may represent one of the parents of the triploid form; perhaps the other is the sympatric bisexual** diploid L. ferreirai (Laguna et al., 2010). Which does still leave the question of how the usual parthenogenesis of the diploid L. percarinatum came to be in the first place.

*Or, as it seems to be called, a 'parthenoform' (presumably to avoid having to refer to a parthenogenetic taxon as a 'species').

**In the sense of possessing two sexes, not the other sense.


Laguna, M. M., M. T. Rodrigues, R. M. L. dos Santos, Y. Yonenaga-Yassuda, T. C. S. Ávila-Pires, M. S. Hoogmoed & K. C. M. Pellegrino. 2010. Karyotypes of a cryptic diploid form of the unisexual Leposoma percarinatum (Squamata, Gymnophthalmidae) and the bisexual Leposoma ferreirai from the lower Rio Negro, Amazonian Brazil. Journal of Herpetology 44 (1): 153-157.

Pellegrino, K. C. M., M. T. Rodrigues, Y. Yonenaga-Yassuda & J. W. Sites Jr. 2001. A molecular perspective on the evolution of microteiid lizards (Squamata, Gymnophthalmidae), and a new classification for the family. Biological Journal of the Linnean Society 74: 315-338.

Rodrigues, M. T., E. M. X. Freire, K. C. M. Pellegrino & J. W. Sites Jr. 2005. Phylogenetic relationships of a new genus and species of microteiid lizard from the Atlantic forest of north-eastern Brazil (Squamata, Gymnophthalmidae). Zoological Journal of the Linnean Society 144 (4): 543-557.

Name the Bug #27

Tomorrow's post will relate to this little fellow and his nearest and dearest:

Anyone out there recognise him?

Attribution, as always, to follow.

Update: Identity now available here. Photo from here.